Frontier Freight implements a voluntary affirmative action program aimed at increasing employment opportunities for racial, ethnic, and religious minorities. Which of the following is true:

a$.$ Frontier Freight should implement hiring and promotion quota establishing pre$-$determined numbers of candidates from each protected group

b$.$ Frontier Freight should create a written plan

c$.$ Frontier Freight should incorporate its affirmative action plan into its decisions to terminate employees

d$.$ Frontier Freight may base its plan on general historical injustice in the workplace and need not perform any detailed analysis of its own workforce